数据结构与算法（九） - · PDF filevoid fstream::open(char*name, openmode mode); //...

2008. 6
http://www.jpk.pku.edu.cn/pkujpk/course/sjjg

2
2
9
9.1
9.2 9.2.1
9.2.2 C++
9.3

3
3
( primary memory main memory ) ( Random Access Memory, RAM )
( cache )
( video memory )
( peripheral storage secondary storage) (G - T 1012B )
(P 1015B )
9.1

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4
9.1
()
()

5
5
9.1

6
6
9.1
bit

7
7
9.1
a b 3
512 1024

8
8
CPU
9.1

9
9
1 = 10-9
1 = 10-3
9.1

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10
KB (kilo byte) 103B ()
MB (mega byte) 106B ()
GB (giga) 109B ()
TB (tera) 1012B ()
PB (peta) 1015B ()
EB = 1018BZB = 1021BYB = 1024B
Googol 10 100
9.1

11
11
9.2

12
12
( logical file )
( physical file )
9.2

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13
9.2

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14
9.2

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15
C++
istream
ostream
iostream
3 ifstream istream
ofstream ostream
fstream iostream
9.2

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fstream
#include // fstream = ifstream + ofstream
void fstream::open(char*name, openmode mode);
// fstream::read(char*ptr, int numbytes); // fstream::write(char*ptr, int numbtyes); //
// seekgseekp//
fstream::seekg(int pos); // fstream::seekg(int pos, ios::curr);
fstream::seekp(int pos); // fstream::seekp(int pos, ios::end);
void fstream::close(); //
9.2

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( buffering ) ( caching )
( page ) I/O
( buffer pool )
9.2

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18
( FIFO )
( LFU )
( LRU )
9.2

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19
1.
2. G
( rpm )
9.2

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9
9.1
9.2
9.3 9.3.1
9.3.2
9.3.3

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()
run
9.3

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22
9.3

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23
9.3
>16
1629
19 31
25 21 56 40
14
35
1629 12
19

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24
9.3
31>21
21
40>29>25
35>31>25
35>2913
56
56>31>29
56>40>35

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// Elem // A n // in out template
void replacementSelection(Elem * A, int n, const char * in, const char * out) {
Elem mval; // Elem r; // FILE * inputFile; // FILE * outputFile;
Buffer input; // bufferBuffer output; // initFiles(inputFile, outputFile, in, out);
initMinHeapArry(inputFile, n, A); // MinHeap H(A, n, n);
initInputBuffer(input, inputFile);
9.3

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for(int last = (n-1); last >= 0;){
mval = H.heapArray[0]; //
sendToOutputBuffer(input, output,
inputFile, outputFile, mval);
input.read(r); //
if (!less(r, mval))
H.heapArray[0] = r; // r
else { // lastrlast
H.heapArray[0] = H.heapArray[last];
H.heapArray[last] = r;
H.setSize(last--);
}
H.SiftDown(0); //
} // for
endUp(output, inputFile, outputFile);
}
9.3

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27
M
M
2M
9.3

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28
9.3

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29
(
)
Huffman
9.3

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30
9.3
1
3
18 4500
123000
6 1500
1
3
750
3*6 + 6*2 + 12 +6= 48
1 2
1 2 3 4 5 6

31
31
9.3

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32
k k
k k-1
k
m k log
km k
9.3

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33
B[3] B[2]
L[1] L[2]
B[1]
B[4] B[5] L[5] L[6]
L[3] L[4]
nLowExt offset (+LowExt)L[i]B[p]ip
p = LowExtinLowExti
LowExtioffseti
21
2
/)(
/)({
n=6, LowExt=4, Offset=7
LowExt + Offset = 2n-1

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L[4]64 L[4]
4
4
8
5
2 4
5
B[1]
B[2] B[3]
B[4] B[5] B[6] B[7]
L[1] L[2] L[3] L[4] L[5] L[6] L[7] L[8]
14
26
.
.
.
22
38
.
.
.
24
30
.
.
.
15
25
.
.
.
16
50
.
.
.
11
28
.
.
.
100
110
.
.
.
18
40
.
.
.
1 2 3 4 5 6 7 8
10 9 20 8 12 90 17
25
.
.
.
15
6
20>15
4
98
5

35
35
9.3
n=6
LowExt=4
Offset=7
LowExtinLowExti
LowExtioffseti
21
2
/)(
/)({
B[3] B[2]
L[1] L[2]
B[1]
B[4] B[5] L[5] L[6]
L[3] L[4]
B[0]

36
36
n
9.3
B[3] B[2]
L[1] L[2]
B[1]
B[4] L[4] L[5]
L[3]
B[0]

37
37
L[8] L[7] L[6] L[5] L[4] L[3] L[2] L[1]
B[7] B[6] B[5] B[4]
B[3] B[2]
B[0]
B[1] 5
2
7
8
1 3 6
1 2 3 4 5 6 7 8
10 9 20 12 90 17
6
15
L[3]>L[4]
3
L[2]L[6]
L[6]

38
38
ADTtemplate
class LoserTree{
private:
int MaxSize; // int n; // int LowExt; // int offset; // int * B; // T * L; // void Play(int p,int lc,int rc,int(*winner)(T A[],int b,int c));
9.3

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ADT
9.3
public:
LoserTree(int Treesize = MAX);
~LoserTree(){delete [] B;}
void Initialize(T A[], int size,int (*winner)(T A[], int b, int c),
int(*loser)(T A[], int b, int c)); // int Winner(); // void RePlay(int i, int(*winner)(T A[], int b, int c), int (*loser)(T A[], int
b, int c)); // i };
// Winner B[0] template
int LoserTree::Winner(){
return (n)?B[0]:0;
}

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template // void LoserTree::Initialize(T A[], int size, int(*winner)(T A[], int
b, int c), int(*loser)(T A[], int b, int c)) {
if (size > MaxSize || size < 2) {
cout

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template
void LoserTree::Play(int p, int lc, int rc, int(* winner)(T
A[], int b, int c), int(* loser)(T A[], int b, int c)){
B[p] = loser(L, lc, rc); // B[p]int temp1, temp2;
temp1 = winner(L, lc, rc);// pwhile(p>1 && p%2) { //
temp2 = winner(L, temp1, B[p/2]);
B[p/2] = loser(L, temp1, B[p/2]);
temp1 = temp2;
p/=2;
} // B[p]B[1]B[p/2] = temp1;
}
9.3
Play B[3] B[2]
L[1] L[2]
B[1]
B[4] B[5] L[5] L[6]
L[3] L[4]
8
10 9 20 6
1
2
12
6
3
5
4B[0]

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RePlaytemplate void LoserTree::RePlay(int i, int
(*winner)(T A[], int b, int c), int (*loser)(T A[], int b, int c)){
if (i n) {
cout

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m k log
km
m
k
9.3

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k n
(kn)(k)
(k+nlog k)
k (k)
(log k)
9.3

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45
9.3
13
2
14
7 6
15 8 10 9
27 42 25
94
6 25 13
44
8 2 9
19
14 10 7
31
94
(a) (b)
376 356

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46
9.3

http://www.jpk.pku.edu.cn/pkujpk/course/sjjg/
2008. 6

数据结构与算法（九） - · PDF filevoid fstream::open(char*name, openmode mode); //...

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